1. Field of Invention
The present invention relates to a method and apparatus for adjusting an image resolution, and more particularly to a method and apparatus for enabling a digital image still to achieve an edge enhancing effect through a composite process, even after the digital image has been scaled or de-interlace scanned.
2. Related Art
In recent years, due to technical breakthroughs, the yields of liquid crystal panel (LCD) manufacturers have been continuously increasing. Therefore, the LCD is not limited to be used in notebooks but has also begun to be used in desktops, and has become the mainstream of the market. What's more, LCD manufacturers have begun to manufacture large-size panels to meet the demands of high definition televisions (HDTVs).
However, although by name called high definition televisions (HDTVs), the high definition quality of a frame mainly depends on the source itself. If the source signals are analog signals, when the analog signals are converted to digital signals, the frame is more likely to be distorted. Preferably, one point on the frame is directly displayed by a corresponding point on a screen, which results in the best displaying effect, i.e., directly displaying pixels. However, since resolutions of HDTVs are different due to different sizes, and even the resolutions of the sources of display frames may not be the same, HDTVs often cannot show the deserved frame quality.
As shown in FIG. 1, it is assumed that the resolution of a source image 210 is Nx×My, and the resolution of an HDTV image 220 is S times of that of the source image, supposing Ns×Ms. Generally, the results of Ns/Nx and Ms/My cannot be multiples of 2. FIG. 2 is a schematic view of the conversion of corresponding pixel values of the source image 210 and the HDTV image 220. Provided that the resolution of the source image 210 is 4×4, and the resolution 220 of the HDTV image is 5×5, it can be seen that the corresponding pixel values are substantially different due to the different resolutions. If inappropriately treated, not only does the edge become fuzzy, but also the whole frame appears unsmooth.